One of the Philippines' most-wanted Muslim guerrillas, allegedly trained by Al Qaeda (search) and linked to numerous Southeast Asian terrorist plots, was in police custody Monday.

Saifulla Yunos (search), the suspected leader of the separatist Moro Islamic Liberation Front's (search) special operations group, was arrested Sunday with an Egyptian man at southern Cagayan de Oro airport as they tried to catch a flight to Manila.

Authorities became suspicious when an ambulance pulled over and delivered Yunos, whose leg was in a cast as part of a disguise and who was traveling under an assumed name.

The Egyptian, Al Gabre Mahmud (search), apparently is on an international terrorist watch list, police intelligence director Chief Supt. Jesus Verzosa said, without elaborating. The Egyptian Embassy could not be reached for comment Monday.

Officials said Yunos could be a crucial link between the MILF and foreign Muslim extremists.

The government last week intensified a military crackdown on the MILF in response to attacks that have killed more than 210 people this year. It has long suspected the group receives support from abroad.

MILF guerrillas claim they are legitimate revolutionaries fighting for an independent Islamic homeland in the southern Philippines and have no ties with foreign terrorist groups.

Police intelligence officials, however, say Yunos is among supporters and trainers of such groups as Jemaah Islamiyah, the alleged Southeast Asian branch of Al Qaeda blamed for several bombing plots, including last year's attacks in Bali, Indonesia, which killed 202 people.

President Gloria Macapagal Arroyo (search) congratulated police on the arrest. "They all worked hard to put this all together. The war against terror is making very, very good progress."

Yunos allegedly worked as a bombing and urban warfare instructor for the MILF and foreign terrorists, who approached him for logistical needs including bombs, police say.

An police intelligence file describes him as "a fanatic of the extreme Islamic fundamentalist movement" who received training in an Al Qaeda camp in Afghanistan, including lessons on using anthrax as a biological weapon.

A fellow trainee, Indonesian Fathur Roman al Ghozi, would later emerge as a key Jemaah Islamiyah operative in Southeast Asia, according to the report. Al Ghozi was arrested in Manila in January 2002, pleaded guilty to explosives possession charges and was sentenced to 10-12 years in prison.

When Jemaah Islamiyah, led by al Ghozi, planned to bomb the Israeli and U.S. embassies and other Western targets in Singapore in 2001, they turned to Yunos to produce five to seven tons of explosives, another police intelligence report said.

In exchange for Yunos' help, al Ghozi gave him about 155 pounds of explosives later used in five almost-simultaneous bombings that killed 22 people in Manila on Dec. 30, 2000, police officials say.

The bombings in Manila were allegedly staged in retaliation for a military offensive that led to the capture of 46 MILF camps earlier that year. The planned Singapore bombings fell through when several plotters were arrested.

In recent months, police have linked Yunos to a series of deadly bombings in the southern Philippines. Police officials began getting leads on his whereabouts about two to three months ago.